Rotary bit



J. T. PHIPPS May 5, 1936.

ROTARY B IT Filed Oct. 29, 1954 2 Sheets-Sheet l o ml J. T. PHIPPS May5, 1936.

ROTARY B I T Filed Oct. 29, 1934 2 Sheets-Sheet 2 Patented May 5, 1936UNITED STATES uvuv- PATENT 'OFFICE ROTARY BIT Application October Z9,1934, Serial No. 750,546

3 Claims.

My invention relates to rotary bits, and has particular reference to thecone-cutter type of rotary bits.

In earth boring it has been the common practice to employ a rotary bitfor the purpose of digging the bottom of the hole and securing in thetool string above the bit a second instrument, or reamer, for thepurpose of finishing off the sides of the earth bore and enlarging thesame to the desired diameter.

Also. it is the common practice to employ a bit structure which includesa body having downwardly extending legs upon which are mounted aplurality of cone-cutters, the surfaces of which are formed with teethto engage and cut formations by the rolling contact of the cone-cutterteeth upon the formation.

Heretofore the only manner in which such cone-cutters could be mountedupon the bit body was by mounting the cutter upon a. bushing whichbushing was then screwed to a pin extending from the bit body, making itnecessary that some locking means be employed between the bushing andthe pin in order to prevent the cone from being lost from the body. Alsothe employment of cone-cutters on a bit constituting one tool andemploying reamers upon a separate tool spaced a considerable distance tothe rear of the cutting surface of the cone-cutters prevents the cleanand rapid cutting of the cone-bit due to the fact that the lead whichthe cone-cutter has over the rearwardly spaced reamers is such that thereamers are required to cut surfaces of considerably greater area thanwould be required if the reamers were placed immediately adjacent theedges of the cone-cutters.

It is, therefore, an object of my invention to provide a rotary bitstructure in which conecutters are mounted upon legs extending from thebit body, by attaching means which extend from the exterior surface ofthe bit body leg into the interior of the cone-cutter.

Another object of my invention is to provide upon a single tool a seriesof cone-cutters and a series of vertically rotated reamers so locatedrelative to the cone-cutters that the cutting surface of the reamersengages the formation but a minute distance rearwardly of the cuttingsurface of the cone-cutters.

Another object of the invention is to provide a blt structure in which asingle bit body is employed to mount both cone-cutters and reamers withthe cutting surfaces of the cone-cutters and of the reamers in closerelation to each other.

Another object o! the invention is to provide a bit structure in which acone-cutter has embodied therewith a disc cutter rotatable upon thecone.

Other objects and advantages of the invention will be apparent from astudy of the following specifications, read in connection with theaccompanying drawings, wherein Figure 1 is a vertical elevational viewof a bit structure constructed in accordance with my invention;

Figure 2 is an end view of the bit assembly shown in Figure 1;

Figure 3 is a vertical sectional view taken along line III-III of Figure2;

Figure 4 is a vertical sectional view taken along line IV-IV of Figure2;

Figure 5 is a horizontal sectional view taken along line V-V of Figure4; and

Figure 6 is a detail view of a modified form of cone structure which maybe employed with my invention.

Referring to the drawings, I have illustrated in Figures 1 to 5 a bitstructure which comprises a body member formed of two complementarysections i and 2, assembled together with their meeting faces joinedalong the line indicated by the reference character 3, the body membersare identical, each including two downwardly depending legs 4 and 5 sothat when the body members are assembled as shown in Figures 1 to 5, thelegs 4 of the two body members will lie on diametrlcally opposite sidesof the Vertical axis of the tool, while similarly the legs 5 will lie onopposite sides of the vertical axis. The upper ends of the body membersI and 2 are formed of complementary sections which together form a conetype pin permitting the connection therewith of the drill stringemployed to rotate the tool.

By referring particularly to Figure 3 it will be observed that the lowerends of the legs 4 and 5 are cut along a line extending at 45 to theaxis of rotation of the tool to form a seating surface for the rear endof a cone-cutter 6 secured upon the legs 4 by means of a bearing pin lextending downwardly through the leg I at an angle of 45 to the verticalaxis of the tool so that by forming the cone-cutter 6 with its outersurfaces arranged at 90 relative to each other the cutting edge 8 of thetool will lie substantially along a horizontal line while the oppositeedge 9 of the cone-cutter will just clear a center line drawn throughthe vertical axis of the tool.

'I'he tool l may be of any suitable material inserted through an angularbore I0 and secured thereto by means of welding or any other wellknownmethod of securing metal parts together.

The pin 1 is illustrated as having its lower end reduced in diameter, asindicated at II so that a shoulder I 2 is formed thereon whichconstitutes an abutting shoulder upon which may be assema wear bushingI3 formed of any suitable hardened wear-resistant material, such bushingconstituting a lining extending substantially over all of the surfacesof the pin upon which the conecutter 6 will bear. Similarly, a hardenedseal washer I4 may be mounted upon the pin l to constitute a thrustwasher against which the rear end of the cone 6 may abut to resist thethrust and wear upon the end of the leg 4. If desired roller bearings I5and I6 may be interposed between the interior of the cone-cutter 6 andthe wear bushing I3 to reduce the friction thereon.

With the construction thus far described the cone-cutter may beassembled upon the pin and its wear bushing from the lower end thereofand the cone-cutter may be held in place by a lock-pin I1 extendingthrough a central bore I8 formed along the longitudinal axis of the pinl, the lock pin I1 extending into threaded engagement with the apexportion of the cone 6 as indicated at I9. The opposite end of thelock-pin I'I is illustrated as being formed with an enlarged head 20receivable in an enlarged bore 2l in the pin I so that the head 20 bearsupon a shoulder 22 formed between the two bores I8 and 2| and preventsany movement of the cutter 6 away from the pin 1. Th ook-pin Il is riered-Gathecutterjtorlota-teftll 'n il .h.means ofar s et screw 23 sothat once assembled the cutter 6 and the lock-pin I1 rotate together.

By referring particularly to Figures 1 and 4, it will be observed thatthe legs 5, extending from the opposite body members I and 2, areprovided with bores 24 which extend in parallel relation to the axis ofrotation of the tool and constitute mounting devices upon whichcylindrical reamer cutters 25 may be mounted upon bearing pins 26 whichextend into threaded engagement with the bores 24. The bearing pins 26are illustrated as being formed with enlarged heads 21 adjacent to whicha radial recess 28 is formed to receive roller bearings 29, forming arotating bearing surface upon which the cylindrical reamer cutters 25may drop from above. The bearing pins 26 may then be screwed into thelegs 5 with a wear washer 30 interposed between the upper edge of thereamers 25 and the lower surfaces of the legs 5. 'I'he bearing pins 26are illustrated as having their upper ends formed with a radial groove3l extending therearound, such radial groove constituting a recessrelative to a horizontal bore 32 extending through the body member uponwhich it is assembled, so that bolts 33 extending through the bores 32at right angles to the dividing line 3 of the body section may beemployed for the double purpose of locking the bearing pins 26 in placein the tool, and for securing the two complementary halves of the bodymember together.

By referring particularly to Figures 3 and 4, it will be observed thatthe location of the reamer cutters 25, relative to the cone-cutters 8,is such that as shown particularly in Figure 4 the cutting line 40 ofthe cone-cutters is spaced but a minute distance below the lowermostcutting surface 4I of the reamer cutters 25 so that the reamer cuttersin effect continue the cut of the cone-cutters with but a minutequantity of material separating the line of engagement of thecone-cutters with the bore from the line of engagement of the reamercutters with the bore.

Likewise, by particular reference to Fig. 3, it will be observed thatthe sides of the reamer cutters 25 will cut along the line indicated bythe reference character 42 which begins but a slight distance rearwardlyof the cutting line of the cone-cutters and reams the hole substantiallyat the point of contact of the cone-cutters with the hole to therequired internal diameter, the entire cut, both at the base of the holeand along the sides of the hole, occurring substantially simultaneouslyand with substantially little material interposed therebetween.

By the use of the construction set forth the reamer cutters 25continuously clear the bore for the cone-cutters, removing the materialfrom that part of the cone-cutters indicated by the arrow 43, whichconstitutes the greatest resistance and the greatest wear in the presenttype of conebits, while, at the same time, the cone-cutterssubstantially start the cut to be made by the reamer cutters since, froman inspection of Figure 4, it will be observed that the line of cutindicated at 40 curves at its end in conformity with the curved rearedges of the cone-cutters and substantially meet the cutting line of thelower ends of the reamer-cutters.

By referring particularly to Figure 6, it will be observed that theassembly of the cone-cutters upon the legs 4 by the employment of thebearing pin I and the lock-pin Il permits the ready separation of thecone-cutter 6 into two parts, 6a and 6b, the apex section 6aconstituting the major portion of the cone extending from its apex,while the base section 6b constitutes in effect a disccutter mounted forrotation upon the cone section 6a. This construction may be readilyformed by constructing a rearwardly extending boss 45 upon the conesection 6a which has an exterior surface concentric with the axis ofrotation of the cone section 6a, upon which boss the section or disc 6bis mounted with roller bearings 46 interposed therebetween, if desired.

It will be noted from an inspection of Figure 6 that the teeth 4l,formed upon the section 6b, are curved to cut the exterior portions ofthe bore including the outer part of the bottom of the bore and aportion of the cylindrical side walls of the bore, and hence do notconform with or form an extension of the straight cutting line of theremainder of the cutter (that is of section 6a) so that there cannot bea true rolling contact achieved between the bore and the teeth of thesection 6b if such section is rigid with the section 6a. Thus therewould be a considerable dragging or scraping between the teeth 4l andthe earth formation. By arranging the section 6b as a separate disc andmounting it for rotation upon the section 6a, it will be apparent thatthe section 6b can rotate independently of the section 6a and thus theteeth 41 will operate as true rolling teeth. Moreover, by mounting thesection 6b for rotation on the section 6a, the differential cutter 6bwill not be subjected to jamming and stoppage in the earth bore becauseeven though such cutter 6b should bind upon its bearing surface thatbearing surface, being a part of the rotating cone 6a, will be rotatedand will tend to move or rotate the section 6b relative to the earthformation, thus assisting in the release of the section 6b should it bejammed in the earth bore.

With the assembly shown in Fig. 6 it will be observed that substantiallyall of the thrust on the cone section 6a will be taken up by the rollerbearings I and I6, section 6b being subjected only to such resistance asis occasioned by its own contact with the earth formation.

While I have shown and described the preferred embodiment of my,invention, I do not desire to be limited to any of the details ofconstruction shown herein, except as dened in the appended claims.

I claim:

1. In an earth-boring tool, a blt body, a cone cutter formed in twosections, an apex section for cutting the central portions of an earthbore and a base section for cutting the exterior portions of an earthbore, ans mounting said apex section of said cutter on/said bit body forrelative rotation thereto, a cylindrical boss formed upon and extendingrearwardly from said apex section to constitute a rotatable bearingmember upon which said base section is rotatably mounted.

2. In an earth-boring tool, a. bit body, a cone shaped cutter formed intwo sections, an apex section for cutting the central portions of anearth bore and a base section for cutting the ex- Uuml VH teriorportions of. the bottom of the earth bore and the side wall oi saidearth bore, means mounting said apex section on said bit body forrotation relative thereto, a cylindrical extension on said apex sectionextending rearwardly. thereof and concentric with the axis of rotationof said apex section to constitute a rotating bearing upon which saidbase section oi' said cutter ls rotatably mounted.

3. In an earth-boring tool, a bit body, a cone shaped cutter formed intwo sections, an apex section for cutting the central portions of anearth bore and a base section constituting a rearward continuation ofsaid cone and having teeth thereon deviating from the cone surface tocut the outer portion of the bottom of said bore and the side wall ofsaid earth bore, means mounting said apex section on said bit body forrotation relative thereto, a cylindrical extension on said apex sectionextending rearwardly thereof and concentric with the axis of rotationofl said apex section to constitute a rotating bearing upon which saidbase section of said cutter is rotatably mounted.

JOHN T. PHIPPS.

IIVV

